Cell therapy for chronic ischemic cardiomyopathy is important and ready for investigation. The myocardium has very limited regenerative potential after infarction, but we and others have shown that regenerative mechanisms do exist, exhibit plasticity, and can be harnessed and amplified towards therapeutic goals. While significant attention has been paid to bone marrow derived cells, it is increasingly appreciated that the heart itself contains resident cardiac stem cells (CSCs) with the potential to differentiate into cardiomyocytes, vascular smooth muscle cells, and endothelial cells. We have found that therapeutic administration of MSCs is followed by dramatic stimulation of host CPCs in vivo, which are recruited to and/or amplified at the site of MSC injection, and which regenerate infarcted myocardium by differentiation into functional cardiomyocytes. These CSCs are a potential therapeutic agent. The overall aim of this project is the preclinical validation of c-kit+ CPC therapy for an FDA IND for a clinical trial. Our in vivo findings demonstrate that the activation of endogenous CPCs by transplanted MSCs results in the replacement of the damaged heart. Additional preliminary data shows that bone marrowderived MSCs, when used as a feeder layer in organotypic cultures of porcine endomyocardial biopsies, hasten a dramatic outgrowth of c-kit+ CPCs with enhanced cardioblastic properties. Here, we hypothesize that adult c-kit+ cardioblasts can be optimally generated from single endomyocardial biopsies, and can be successfully expanded into therapeutic quantities. We will transplant c-kit+ CPCs alone and in combination with MSCs into a validated preclinical model of heart failure, the Gottingen miniswine. The goals of this work are to obtain safety and efficacy data to support an FDA IND, and to study the regenerative effects of these cell-based therapeutic strategies. Accordingly, this study will support the transition of CPCs from the laboratory to clinical practice. This program of work will allow an orderly progression of studies with the overall aim of developing a novel cell-based therapy that will address major unmet needs in cardiovascular medicine. RELEVANCE: (See instructions): Cell-based therapies for myocardial infarction are currently under evaluation and are emerging as a promising new therapy. Here we propose the use of highly cardiopoetic cardiac progenitor cells. Cells will be tested in a porcine model in preparation for an FDA IND. The results of this trial will advance the field greatly by introducing a novel cell-based therapy for chronic ischemic heart disease,